Make crumble mix by rubbing together the sugar, butter and flour to a breadcrumb texture
Preheat the oven to 180ºc/160ºc fan and line a 9” square tin with parchment paper, leaving a little overhang up the sides to lift the cake out later
Beat the butter and sugar until creamy
Add flour, eggs, vanilla, ground ginger and mix
Fold the rhubarb through the cake mix and pour into the tin (this is my default method). Alternatively, pour the plain cake mix into the tin and scatter the rhubarb over the top.
Sprinkle over the crumble mixture
Bake for 40-45 minutes, until the top is golden and a skewer inserted into the centre of the sponge comes out clean, leave to cool for a while and then enjoy!
Notes
This cake will last for 3+ days at room temperature